Clustering with k-means is well-established and efficient, but often struggles with complex data distributions because the clustering performance hinges on how well the centroids capture the data distribution, and conventional k-means usually fails to produce representative centroids under such conditions. To address this limitation, we propose Pseudo Multi-view K-means Clustering (PMKC), a novel framework that simulates a multi-view learning paradigm within a single-view setting by generating multiple soft k-means decompositions. Each decomposition can be treated as an individual view and investigates a distinct perspective of the data. Specifically, to encourage complementary structure, we impose an independence constraint among cluster centers, and to integrate these diverse clusterings, we model the soft assignment matrices as a third-order tensor and apply low-rank regularization to extract a shared latent structure. This design not only enhances clustering robustness but also improves the stability and consistency of the final results. Experimental results on several benchmark datasets demonstrate that PMKC achieves superior clustering performance compared to state-of-the-art methods.

The Mainstream 3D masked point modeling representation learning community typically employs predefined, fixed-ratio random or block masking strategies, aiming to obtain optimal representations and achieve high downstream performance. However, these empirical designs overlook the significant geometric information and structural importance differences that are inherent among different 3D points, leading to a suboptimal trade-off between the representation capture capabilities and reconstruction difficulty of such masking strategies. To address this issue, we are the first to present this decision-making problem to a reinforcement learning agent and propose a Reinforcement Masked Autoencoder for 3D representation learning, named Point-RMAE. Guided by geometric features as state factor, this method leverages the Masking Strategy Analyzer and the Dynamic Masking Generator to adaptively decide and apply the masking strategy during pretraining. The Masking Ratio Scheduling module dynamically adjusts the masking ratio based on the optimal strategy. Subsequently, the analyzer is updated by multiscale rewards derived from reconstruction quality level, distribution-aware feedback, and policy exploration. Notably, to enrich the Reward Function with distribution-aware signals and avoid decision collapse issue, we propose a Flow Matching Point Cloud Fast Generator that guides the selected masking decisions. Our method achieves outstanding performance across downstream tasks such as shape classification, medical diagnosis, object detection, action recognition, denoising and multiscale scene segmentation on ten popular 3D and 4D datasets. More importantly, Point-RMAE pioneers the application of reinforcement learning in 3D self-supervised representation learning.

Multi-view clustering (MVC) aims to extract consensus information from multi-source data and has developed rapidly. While generative model-based methods perform well by leveraging predefined priors, they often overlook inter-instance relationships, which are essential for high-quality clustering. To address this issue, we propose Graph Variational Multi-view Clustering (GVMVC), which integrates graph information into the generative process. Specifically, we treat both the original multi-view features and graph information from each view as observed data, guiding the learning of latent representations. The key principles of this approach are: 1) enhancing discriminative feature learning through graph integration, and 2) ensuring consistent multi-view learning via graph-based constraints. Extensive experiments show that GVMVC outperforms state-of-the-art methods across various datasets and metrics. Code is available at https://github.com/WenB777/GVMVC.git.

Driven by the complementarity and consistency inherent in multiview data, multiview clustering (MVC) has garnered widespread attention in various domains. Real-world data often encounters the issue of missing information, leading to a surge of interest in the domain of incomplete MVC (IMVC). Despite existing approaches having made significant progress in addressing IMVC, two significant challenges persist: 1) many alignment-based methodologies tend to overlook the topological relationships among instances and 2) the view representations based on completion lack reconstructive properties, casting doubt on their alignment with the actual view representations. In response, we present a novel approach termed neighbor-based completion for addressing IMVC (NBIMVC), which capitalizes on the topological information among instances and the consistent information across views. Specifically, our method uses autoencoders to learn feature representations for each view and leverages nearest-neighbor relationships between unique and complete instances to complete missing features in missing views. Subsequently, we enforce hard negative alignment constraints on complete paired instances in the feature space. Finally, we ensure the consistency of views in the semantic space by employing cluster information and a shared clustering network, which facilitates the final multiview categories output and effectively resolves the IMVC problem. Extensive experimental evaluations validate the efficacy of our proposed method, showcasing comparable or superior performance to existing approaches.

Federated learning encounters substantial challenges with heterogeneous data, leading to performance degradation and convergence issues. While considerable progress has been achieved in mitigating such an impact, the reliability aspect of federated models has been largely disregarded. In this study, we conduct extensive experiments to investigate the reliability of both generic and personalized federated models. Our exploration uncovers a significant finding: federated models exhibit unreliability when faced with heterogeneous data, demonstrating poor calibration on in-distribution test data and low uncertainty levels on out-of-distribution data. This unreliability is primarily attributed to the presence of biased projection heads, which introduce miscalibration into the federated models. Inspired by this observation, we propose the "Assembled Projection Heads" (APH) method for enhancing the reliability of federated models. By treating the existing projection head parameters as priors, APH randomly samples multiple initialized parameters of projection heads from the prior and further performs targeted fine-tuning on locally available data under varying learning rates. Such a head ensemble introduces parameter diversity into the deterministic model, eliminating the bias and producing reliable predictions via head averaging. We evaluate the effectiveness of the proposed APH method across three prominent federated benchmarks. Experimental results validate the efficacy of APH in model calibration and uncertainty estimation. Notably, APH can be seamlessly integrated into various federated approaches but only requires less than 30% additional computation cost for 100x inferences within large models.

3D Masked Point Modeling (MPM) typically involves randomly or blockly discarding points or patches and then reconstructing them, offering a promising avenue for exploring geometric representation. By surveying current masking strategies, we have found that random-masked regions are provided with excessive context, reducing modeling difficulty but impeding knowledge transfer. While, block-masked regions lack sufficient guidance, resulting in significant generated noise. To address these issues, we propose PTM, a novel Transformer-style 3D MPM method employing a torus masking strategy. Specifically, a high-density area is chosen as the masked region, forming a torus by retaining small-radius neighborhoods around the center point. To mitigate torus modeling noise, the designed robust teacher model captures density scale to construct noise embedding, utilizing a reverse fit function for reconstruction assistance. Furthermore, the proposed trusted teacher model defines the multi-modal global descriptor as subjective evidence. On a semantic level, we form semi-subjective trusted evidence to guide reconstruction by evaluating the contribution of each subjective evidence to 3D representation. Downstream fine-tuning tasks validate the state-of-the-art performance of PTM in multi-scale point cloud classification and segmentation.

Federated learning encounters a critical challenge of data heterogeneity, adversely affecting the performance and convergence of the federated model. Various approaches have been proposed to address this issue, yet their effectiveness is still limited. Recent studies have revealed that the federated model suffers severe forgetting in local training, leading to global forgetting and performance degradation. Although the analysis provides valuable insights, a comprehensive understanding of the vulnerable classes and their impact factors is yet to be established. In this paper, we aim to bridge this gap by systematically analyzing the forgetting degree of each class during local training across different communication rounds. Our observations are: (1) Both missing and non-dominant classes suffer similar severe forgetting during local training, while dominant classes show improvement in performance. (2) When dynamically reducing the sample size of a dominant class, catastrophic forgetting occurs abruptly when the proportion of its samples is below a certain threshold, indicating that the local model struggles to leverage a few samples of a specific class effectively to prevent forgetting. Motivated by these findings, we propose a novel and straightforward algorithm called Federated Knowledge Anchor (FedKA). Assuming that all clients have a single shared sample for each class, the knowledge anchor is constructed before each local training stage by extracting shared samples for missing classes and randomly selecting one sample per class for non-dominant classes. The knowledge anchor is then utilized to correct the gradient of each mini-batch towards the direction of preserving the knowledge of the missing and non-dominant classes. Extensive experimental results demonstrate that our proposed FedKA achieves fast and stable convergence, significantly improving accuracy on popular benchmarks.